The House was in session for less than an hour on Monday and the Senate for less than 20 minutes. As such, the day's Congressional Record, reporting the proceedings of both houses, could have been as slim as a reed.

Why, then, does it have the girth of a Russian novel and the price tag of a house in the suburbs?

Because Rep. William V. (Bill) Alexander Jr. (D-Ark.) took it upon himself -- at an estimated cost to the government of $197,382 -- to insert into the Record 3 1/2 years of legislative debate in the House and Senate on the Boland Amendment barring military aid to the contras fighting the government of Nicaragua.

It was the longest insertion in the Record in at least 20 years, according to a Government Printing Office (GPO) spokesman. Told this, Alexander didn't blink.

"The cost of U.S. policy in Central America is more than a billion dollars," said Alexander, a stern opponent of that policy. "If this information is used properly, it could save us billions of dollars."

The 403 pages of debate include no mention of presidential immunity, which President Reagan has asserted during the unfolding Iran-contra investigation, Alexander observed. "I wanted to put the entire debate in one compendium in order that people could judge for themselves whether or not the president's defense was credible and legal," he said.

To the surprise of many who saw yesterday's Record, Alexander's publishing binge fell fully within the laws and rules of Congress. The only limit on the amount of verbiage lawmakers insert into the Record is a requirement that, for remarks extending beyond two pages, they publish the GPO's cost estimate of printing them. They also must get unanimous consent from colleagues in their chamber -- generally bestowed on request.

Alexander did both, although a range of House members interviewed yesterday said they had no idea what they were consenting to.

Minority Leader Robert H. Michel (R-Ill.), described by an aide as "galled" when he saw the Record, took the floor yesterday to tell GOP leaders and staffs to object to all future insertions that would cost more than $10,000 to print. "We have gotten quite excessive lately. And it's just got to stop," Michel said.

"I also will have my floor representatives require that every such request must be made at a microphone so that all can clearly understand exactly what the request was," Michel added.

Alexander, a 10-term congressman, was a rising star in the House and a candidate for the No. 3 post of majority whip until it was revealed in 1985 that, at a cost of $50,000, he requisitioned a Pentagon plane to fly him to Brazil to study alcohol-based fuel. Alexander dropped out of the whip's race.

There was conspicuous silence among most Democrats about Alexander's latest move. Questions about the merits of the printing went unanswered by the offices of Rep. Edward P. Boland (D-Mass.), author of the amendment, and Sen. Daniel K. Inouye (D-Hawaii), chairman of the Senate select committee investigating the Iran-contra affair.

Rep. John McK. Spratt Jr. (D-S.C.), who was presiding in the House when Alexander announced he was going to insert the full record of the Boland debate, said the floor was almost empty and no one objected. Spratt said he did not hear Alexander state the printing cost, although the Record quotes it.

"I was presiding over the routine passage of two noncontroversial bills and I didn't have any advance notice of what Bill Alexander intended to do," Spratt said. "I would have been shocked if I had heard that {cost figure}."

The money for the Record comes from a congressional printing and binding fund. An expert on the fund said the GPO's $197,000 estimate is likely inflated because the history did not have to be typed. It was retrieved electronically from earlier Congressional Records.

"It cost a lot, but probably no more than the collective cost of members who insert the favorite apple pie recipe" of some constituent, the expert said.

Rep. Henry J. Hyde (R-Ill.), a contra-aid proponent, said he learned of Alexander's actions when he flipped through the Congressional Record and was perplexed to find the names of many members no longer in the House. He then realized he was reading a history.

"It's difficult for those of us who are Republicans and defending the administration to complain because they'll say we're trying to cover up or obscure the truth," Hyde said. ". . . But if Mr. Alexander is so interested in having this all in one publication, perhaps the Democratic National Committee should have paid for it."